Operating the LCLS Gas Attenuator and Gas Detector System with Apertures of 6 mm Diameter

[摘要] The possibility of increasing the apertures of the LCLS gas attenuator/gas detector system is considered. It is shown that increase of the apertures from 3 to 6 mm, together with 4-fold reduction of the operation pressure does not adversely affect the vacuum conditions upstream or downstream. No change of the pump speed and the lengths of the differential pumping cells is required. One minor modification is the use of 1.5 cm long tubular apertures in the end cells of the differential pumping system. Reduction of the pressure does not affect performance of the gas attenuator/gas detector system at the FEL energies below, roughly, 2 keV. Some minor performance degradation occurs at higher energies.

[发布日期] 2008-10-27

[学科分类] 物理（综合）

[关键词] APERTURES;MODIFICATIONS;PERFORMANCE;PUMPING;VELOCITY